I'm investigating the X2 for an outdoor security application to detect intrusion into a space (perhaps a 20m radius). My primary restriction is that the packaged device would have to be in a cylinder with a maximum diameter of about 3 inches and about 6 inches tall. I see that the chips+salsa boards use two antennas that are separated in the X-Y plane. Would it be possible to stack them in the Z plane? I'm not sure what that would do to the antenna pattern but I'm primarily interested in detecting movement in the X-Y plane. Is the pattern of the antennas on the demo boards approximately uniform in that plane?